STOP 7b – INACCESSIBLE_BOOT_DEVICE – not only can this mean that the storage driver isn’t loading but it can also be caused by something like a chipset driver not loading.  In particular, something in the CriticalDeviceDatabase.  I have seen this crop up with Roxio’s drvmcdb.sys file.   This is registered in the registry as a service.  This service is listed as a lower filter on the CD-ROM class in the registry and the CD-ROM service is listed in the CriticalDeviceDatabase. So, if there is a problem with the drvmcdb.sys file then Windows won’t load with a 7b code.

STOP C2 – BAD_POOL_CALLER – I’ve seen this caused by a corrupt ntuser.dat for one of the machine’s users.  It took ages to troubleshoot this one, because even doing a repair install of Windows will not stop it.  Setup will BSOD at “Completing Installation” with 24 minutes left.  Restoring a backup from the System Volume Information cures it.